The present invention concerns agricultural sprayers designed for the spreading of crop treatment products, herbicides, fungicides, and particularly fertilizers in suspension.
These machines comprise one or more spray booms deployed above the soil and projecting conically shaped sprays of product against it. To this end, the boom or booms are equipped with spray nozzles aimed at the ground.
It is important during the spreading of a product to spray all of the surface under treatment without skipping and without any overlapping of sprayed areas.
Now, the spray that is applied to the soil by a nozzle strikes the ground in a pattern of circular or nearly circular elliptical shape, whose size depends on the height of the nozzle above the ground and on the pressure of the liquid being sprayed. For a given height of the spray boom above the ground, the total area sprayed will depend on the pressure of the liquid being sprayed. The greater the pressure is, the closer the cone will approach the theoretical cone defined by the design spray angle of the nozzle. On the other hand, as the pressure diminishes, the spray coverage tends to be reduced by the action of gravity.
It is also easy to understand that such variations of the area sprayed with the pressure of the liquid are amplified when wide-angle spray nozzles are used. It is evident that, if variations occur in the spray pressure, while the height of the spray nozzles above the ground remains the same, there is a danger that overlapping of the spray cones will occur, or, on the other hand, that areas of the soil will fail to be covered by the spray.